class RuboCop::Cop::Performance::Count

Model.where(id: [1, 2, 3]).to_a.count { |m| m.method == true }
becomes:
Model.where(id: [1, 2, 3].select { |m| m.method == true }.size
Example:
make ‘count` work with a block is to call `to_a.count {…}`.
array and then run the block on the array. A simple work around to
Other methods, such as `select`, will convert the association to an
`ActiveRecord` will ignore the block that is passed to `count`.
`ActiveRecord` compatibility:
Model.select(:value).count
Model.select(’field AS field_one’).count
[1, 2, 3].count { |e| e < 2 && e.even? }
[1, 2, 3].count { |e| e > 2 && e.odd? }
[1, 2, 3].count { |e| e < 2 }
[1, 2, 3].count { |e| e > 2 }
# good
array.select(&:value).count
[1, 2, 3].reject { |e| e > 2 }.count { |e| e.even? }
[1, 2, 3].select { |e| e > 2 }.count { |e| e.odd? }
[1, 2, 3].reject { |e| e > 2 }.length
[1, 2, 3].select { |e| e > 2 }.length
[1, 2, 3].reject { |e| e > 2 }.size
[1, 2, 3].select { |e| e > 2 }.size
# bad
@example
passed to the ‘count` call.
follow calls to `select` or `reject`. Querying logic can instead be
This cop is used to identify usages of `count` on an `Enumerable` that

def autocorrect(node) 

def autocorrect(node)
  selector_node, selector, _counter = count_candidate?(node)
  selector_loc = selector_node.loc.selector
  return if selector == :reject
  range = source_starting_at(node) { |n| n.loc.dot.begin_pos }
  lambda do |corrector|
    corrector.remove(range)
    corrector.replace(selector_loc, 'count')
  end
end

def eligible_node?(node) 

def eligible_node?(node)
  !(node.parent && node.parent.block_type?)
end

def on_send(node) 

def on_send(node)
  return if rails_safe_mode?
  count_candidate?(node) do |selector_node, selector, counter|
    return unless eligible_node?(node)
    range = source_starting_at(node) do
      selector_node.loc.selector.begin_pos
    end
    add_offense(node,
                location: range,
                message: format(MSG, selector: selector,
                                     counter: counter))
  end
end

def source_starting_at(node) 

def source_starting_at(node)
  begin_pos = if block_given?
                yield node
              else
                node.source_range.begin_pos
              end
  range_between(begin_pos, node.source_range.end_pos)
end